Recently, due to the accelerated supply of smart phones, the amount of mobile data traffic has rapidly increased. Further, since application services such as a Social Network Service (SNS) and games using the smart phone are expected to gradually become more dynamic, the mobile data traffic will increase more and more. In order to solve a problem of a traffic overload concentrated at an evolved NodeB (eNB) or an Access Point (AP) due to the rapid increase of mobile data traffic, a Device-to-Device (hereinafter, referred to as “D2D”) communication technology is spotlighted. The D2D communication refers to direct communication between adjacent User Equipments (UEs) without infrastructure configured by a centralized access point such as the eNB or the AP.
When the D2D communication technology is combined with a mobile communication system, traffic capacity of the base station may increase and overload may decrease, which is worthy of notice. That is, when UEs within the same cell or adjacent cells establish a D2D link therebetween and directly exchange data through the D2D link without passing through the eNB, there is an advantage in that two links can be reduced to one link.
Accordingly, interest in a discovery procedure for efficiently operating a process in which a plurality of UEs broadcast information on service contents around the UEs and receiving the information has rapidly increased. For example, an Over-The-Top (OTT) scheme of discovering an adjacent UE is provided by collecting application program information and service-related information from the UE based on the existing Internet network, identifying whether another UE associated with the collected information is located within a range in which a service is available, and informing each UE of a result thereof, by an Application Service Providing (ASP) server. The conventional OTT scheme spent many network resources during a process of periodically transmitting location information and user/service recognition information to a server and receiving a result from the server in order to find a relevant service based on location information of each of the UEs. Further, the OTT used a significant amount of power since the location should be recognized using an additional device such as a GPS or a short-range WLAN module in order to transmit location information of the UE to the server. In addition, the OTT has a disadvantage in that supporting a D2D communication service is difficult when the number of UEs is large or a discovery range is large since a non-licensed band is mainly used in short-range wireless communication.